Manafort says in a Justice Department filing Tuesday that his firm, DMP International, received more than $17 million from the Party of Regions, the former pro-Russian ruling party in Ukraine, for consulting work from 2012 through 2014.

Manafort helmed Trump's campaign for about five months until August and resigned from the campaign immediately after The Associated Press reported on his firm's covert Washington lobbying operation on behalf of Ukraine's ruling political party.

He is one of several people linked to the Trump campaign who are under scrutiny by a special counsel and congressional committees investigating Russian meddling in the 2016 campaign and potential coordination with Trump associates.

Behind the investigations into Trump associates' ties to Russia

Manafort has denied any coordination with Russia and has said his work in Ukraine was not related to the campaign.

The Washington Post first reported Manafort's registration and posted a copy of his filing online Tuesday. The filing does not bear the date and time stamps showing that it has been formally received by the Justice Department's FARA unit. But Manafort spokesman Jason Maloni confirmed to several news outlets that Manafort had gone through with the registration.

Maloni did not respond to phone calls or emails from the AP seeking comment.

His registration came more than two months after Maloni told the AP that Manafort would be registering under the Foreign Agents Registration Act. Maloni later backed off that statement, saying in late April that Manafort was still considering his options after receiving guidance from the Justice Department.

Under federal law, people who represent foreign political interests and seek to influence U.S. public opinion and policy are required to register with the Justice Department before they perform any work. Manafort's registration comes more than three years after he completed his work.

The Justice Department rarely prosecutes violations of the Foreign Agents Registration Act. Instead, as in Manafort's case, the department often work with lobbyists to get in compliance.

Manafort deputy, Rick Gates also registered for the Ukrainian political work. Gates also served in the Trump campaign. He could not be immediately reached for comment Tuesday evening.

In the filing, Manafort said that his company's work was mostly focused on domestic Ukrainian politics as part of its work for the Party of Regions, which was led at the time by former Ukrainian President Viktor Yanukovych. The filing repeatedly states that Manafort's firm worked "to advance the goal of greater political and economic integration between Ukraine and the West."

Manafort's firm also acknowledged that it had some involvement with a Brussels-based nonprofit called the European Centre for Modern Ukraine, saying that it provided "advice" to the entity.

Last August, the AP reported that emails show that Manafort's firm and Gates directed the efforts of Washington lobbying firms that were working on behalf of the center.

The emails show Gates directing lobbyists from Washington firm Mercury LLC to set up meetings between a top Ukrainian official and senators and congressmen on influential committees involving Ukrainian interests. Gates also had the firms gather information in the U.S. on a rival lobbying operation and directed efforts to undercut sympathy for Yulia Tymoshenko, an imprisoned rival of Yanukovych.

Both of the lobbying firms involved in the work- Mercury and The Podesta Group - have since registered with the Justice Department as foreign agents.